￼￼Some Power Grids Use High-Voltage Direct Current

In the last 100 years, most electric grids have been built using alternating current (AC). But more recent innovations in power electronics extend AC systems with high voltage direct current (HVDC) voltage conversion and power transmission, according to Navigant Research, which says that as of 2013, up to 660 MW of New York City’s load demand is supplied through a back-to-back high-voltage direct current (B2B HVDC) converter in New Jersey.

While the Hudson Transmission Partners (HTP) project in New York and New Jersey represents just one short link in the power system, it signifies the potential for HVDC to creatively solve the most demanding problems in transmission all over the world, according to Navigant’s report “High-Voltage Direct Current Transmission Systems.”

Overall, Navigant Research estimates that the HVDC transmission market constitutes about 333 GW of new transmission capacity between 2013 and 2020. For comparison, peak demand in the United States is estimated to be about 800 GW in 2013.

Growth in electricity demand is only one driver in the growth of HVDC. Adverse effects of transmission system congestion and instability need to be fixed. HVDC allows interconnection of regional systems that operate asynchronously, which mitigates many instability issues that otherwise would cause outages in AC transmission.